In recent years, a mixed reality or so-called MR technique has been known as a technique for blending the physical world and a virtual world in real time and seamlessly. One known MR technique is a technique in which a HMD apparatus user views a synthesized video in which CG (Computer Graphics) is superimposed on a captured video that is captured by a video camera utilizing a video see-through HMD (Head Mounted Display). This captured video is captured so to include a subject approximately matching a subject viewed from a pupil position of the HMD apparatus user. The generation of a synthesized video can be performed by an external server capable of communication with the HMD, and in such cases, the captured video is transmitted from the HMD to the server, and the synthesized video is transmitted from the server to the HMD.
Also, an HMD system mounting a sensor that detects a movement of the head in order to display CG appropriately in correspondence with the movement of the head of the HMD apparatus user is known (Japanese Patent No. 3724157). In such a system, in addition to the captured video, other communication data (data of the sensor that detects the movement of the head, for example), is transmitted from the HMD to the server.